Some photoelectric conversion devices for use in solar photovoltaic power generation and the like include light-absorbing layers made of chalcopyrite-based group I-III-VI compound semiconductors such as CIS and CIGS. Such a photoelectric conversion device is disclosed, for example, in Japanese Patent Application Laid-Open No. 8-330614 (1996) (which is referred to hereinafter as Patent Literature 1).
The group I-III-VI compound semiconductors, which are high in optical absorption coefficient, are suitable for the reduction in thickness of photoelectric conversion devices, the increase in area thereof and the suppression of manufacturing costs thereof. Research and development of next-generation solar cells using the group I-III-VI compound semiconductors has been promoted.
A photoelectric conversion device including such a group I-III-VI compound semiconductor is configured to include a plurality of photoelectric conversion cells arranged two-dimensionally in juxtaposition. Each of the photoelectric conversion cells includes a lower electrode such as a metal electrode, a semiconductor layer including a light-absorbing layer, a buffer layer and the like, and an upper electrode such as a transparent electrode and a metal electrode, which are stacked in the order named on a substrate made of glass and the like. Adjacent ones of the photoelectric conversion cells are electrically connected in series with each other by electrically connecting the upper electrode of one of the adjacent photoelectric conversion cells and the lower electrode of the other of the adjacent photoelectric conversion cells with a connection conductor.